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Maddness utter maddness
Oliver Coles - 22/12/05 at 03:13 PM

Hi

Is it possible to build two Reliant 850cc engines together to form a straight 8? This is something that has been eating away at my brain for ages.

smart51 - 22/12/05 at 03:16 PM

You would have to find some way of coupling the flywheel side of one crank to the timing belt end of the other. It's probably possible. You would end up with a 1.7 litre76 BHP straight 8. Why not just fit a good engine?

Gav - 22/12/05 at 04:01 PM

quote:
Originally posted by smart51
Why not just fit a good engine?


Why build a Locost?
Because you can

zilspeed - 22/12/05 at 04:02 PM

I remember it being done with two Alfa twin cams to make a straight eight. This was back in the early 80s - when all the good stuff happened.

MikeR - 22/12/05 at 04:49 PM

i've often wondered this....

what about 2 3cylinder turbo diatsu engines? 1 litre, all alloy, 100bhp per engine ....

sort of appeals

(ok, the whole engineering principle of bolting two engines appeals)

Volvorsport - 22/12/05 at 05:06 PM

volvo 6 cyl 204 hp , nuff said

Peteff - 22/12/05 at 05:09 PM

What you on about man? We're talking Reliants here.
This is something that has been eating away at my brain for ages. You want to sit and read a book or something, occupy your mind a bit.

akumabito - 23/12/05 at 12:48 PM

quote:
Originally posted by Volvorsport
volvo 6 cyl 204 hp , nuff said


408 Hp straight 12?

Volvorsport - 23/12/05 at 02:07 PM

yeah , but the point of me posting was - its easier to fit a bigger engine in the first place - unless youre going for a land speed record or somert .

rusty nuts - 23/12/05 at 04:07 PM

Last time I looked Reliant's didn't have a timing belt

akumabito - 23/12/05 at 04:40 PM

quote:
Originally posted by Volvorsport
yeah , but the point of me posting was - its easier to fit a bigger engine in the first place - unless youre going for a land speed record or somert .


i know, but rediculously big and/or overly complicated engines have an inherrent cool-factor about 'm

Even though they are quite pointless in most cases..

For example, how could anyone possibly NOT like the Blastolene Special? (no, environmentalists don't count on this one. )

Blastolene Special Movie

smart51 - 23/12/05 at 10:46 PM

quote:
Originally posted by Peteff
What you on about man? We're talking Reliants here.
This is something that has been eating away at my brain for ages. You want to sit and read a book or something, occupy your mind a bit.


I actually have a book. It is a haynes manual for a reliant. Reliant 848cc engines have a timing chain in fact. Even a reliant engine has a cam shaft that has to be driven some how from the crank. On a reliant engine, this is mounted on the other end from the flywheel. The chain from the crank to the cam sits under a cover. the crank pokes out through that cover and a belt drives the alternator, coolant pump and cooling fan. When I said joing the flywheel end of one engine to the timing belt end of the other, this is what I meant:

If you want to join two 4-cylinder engines together to make a straight 8, then you will need to join the two cranks together. You will need to join the flywheel end of one engine (this is the end with the flywheel on it) to the timing chain end of the other engine (this is the end with the timing chain on it as described above). This other engine will have a flywheel on it all of it's own. This can be used in conjunction with a clutch and gearbox to transfer power to the rear axle.

Mr. Peteff, Just how is it that you think that reliant engines don't have a timing belt or chain? How did you assume that the camshaft was driven?

smart51 - 23/12/05 at 10:49 PM

quote:
Originally posted by rusty nuts
Last time I looked Reliant's didn't have a timing belt


No, in fact they have a timing chain. I stand corrected. They do the same thing though.

MikeR - 23/12/05 at 11:09 PM

ok, taking this to another level here....


lets just pretend we're serious (its christmas after all)

would you try to mount both engines solidly onto a frame with a solid 'bolted' crank or would you include some sort of compliant 'bit' between engines? if compliant, how far would you go?

I'd probably solid mount both engines but still aim for a compliant join just cause i'm certain not to have got both engines perfectly in line.

smart51 - 24/12/05 at 10:43 AM

Some of the test rigs in the labs at work couple two powered shafts. There are various solutions.

1) a coiled "bellows". This allows both an angular offset and a step displacement.

2) a prop shaft. possibly with rubber complient joints rather than UJ or CV joints.

Either you would have to line them up perfectly or you would have to allow for some movement or vibration. I would do the latter.


Another point. You would probably have to remove the oil and water pumps plus the alternator from the engine being connected to at the timing end. the alternator at the front may be enough but you'll have to find some way of pumping the fluids.

MikeR - 24/12/05 at 11:46 AM

why?

if you're 'bolting' to the crank pulley (ok, i'm thinking crossflow here as its what i've seen the most of) then everything else can just run around the crank adaptor.

Keeps it simple then otherwise you're going to be into electric water pumps and the like.

(probably would be ok without a second alternator.)

smart51 - 25/12/05 at 11:25 PM

If you can bolt your coupling to the pulley then you might be fine. I still don't know why you'd want to do it. The reliant engine is very light but not very powerfull. It's advantage is that it is so light. Two of them is not so light anymore. If you are going to go to some trouble, better to fit a better engine than two Reliant ones. Each to their own though

MikeR - 27/12/05 at 05:06 PM

Smart - youre completely right, i'm just interested in the engineering principle + the cool factor of having two engines....

ok, how about 2 'k' series engines. They're suppossed to be light and reasonably powerful!!!!

Anyone fancy a 3.6l 32v 380bhp monster?

steve m - 27/12/05 at 06:12 PM

and "WHY" is the main question here

if you want a v8, buy a v8 and stick the thing into a chassis, why try and make things difficult,


ooopps my mistake, about 50% on here are way way out of their depth anyway

MikeR - 27/12/05 at 06:17 PM

Can't speak for others, but the chances of me ever doing this are close to 0. As i said its a nice pipe dream.

But most of you have to admit, if someone did turn up in a car (not suggesting locost / 7) that had two engines bolted together you'd be curious.

I remember how most people reacted to the twin engined bec's when they first turned up. Still love the twin engineed mini idea. If the damned rear tie bar (or what ever it was) hadn't failed almost killing cooper i think BL / BMC / Austin would have made a few of them for a while (different configuration but its the general principle of something done differently that works that fascinates.)

smart51 - 29/12/05 at 09:38 PM

Bolting 2 KV6 engines together or two RV8s. Now THAT would be interesting. A 5 litre V12 or an 8 litre V16?

Could you put two 4 cylinder engines side by side and have a gear wheel engaged with both flywheels? The teeth round the flywheel are only designed for the starter motor but flywheels can be replaced with something more robust. Perhaps a motorcycle chain.

MikeR - 29/12/05 at 09:40 PM

you would have to angle the engines otherwise the inlet of one would interfere with the exhaust of the other.

2 KV6's now thats really starting to appeal ........... light, v6 sound and reasonable power.......

hmmmmmm